Marco Polo, shown here arriving from India at Hormuz on the Persian Gulf, was a forerunner to today's global traders

A FEW years ago a cranky French cheesemaker called José Bové drove his tractor to the site where a McDonald's restaurant was being built. As journalists and camera crews looked on, he and a band of rustic confrères tore the place apart. They did this, Mr Bové explained, not only because burgers are a disgusting expression of American culinary imperialism but also in protest at “what the WTO and the big companies want to do with the world”.

Quite a lot of us derive our patchy understanding of globalisation from such well-publicised high jinks. Often, little in the way of independent thought is brought to bear on the “burgers plus big companies equals bad” style of arithmetic. Nayan Chanda, director of publications at the Yale Centre for the Study of Globalisation, provides background facts for less lazy thinking in a lively book that is packed with incident, anecdote and derring-do.

He points out that globalisation is a new word to describe an old process. The word was introduced in the late 1970s and had gained widespread currency by 1999, the time of Mr Bové's visit to McDonald's. Many thought it described a wholly novel phenomenon. But globalisation really began about 60,000 years ago, when the first migrants walked out of Africa. Human history ever since has been a process of growing interconnectedness.

Mr Chanda organises his argument around what he takes to be the four groups that have done most to bring about this interconnectedness: traders, preachers, adventurers and warriors. Though the motives of these groups—to profit, convert, learn or conquer—have usually been selfish, the overall effect of their actions has been to draw us all closer together.

The four groups are still with us, though some have changed more than others over the centuries. The preachers are going strong, but they now have competition from secular NGOs whose “missionaries” preach human rights and the need to take care of the environment. And while some of us might fancy ourselves as adventurers, we have for the most part degenerated into cheap-flight-enabled tourists—Vasco da Gama and Ibn Battuta would not be impressed.

Mr Chanda traces advances in trading practices and technology—from donkeys and camels to container ships and cargo planes—but is just as good at pointing out deep historical continuities. Frequently he lets figures from the past speak for him in their own words. “The extension and use of railroads, steamships, telegraphs, break down nationalities and bring peoples geographically remote into close connection commercially and politically. They make the world one, and capital, like water, tends to a common level.” The diction aside, it might be a World Bank press release written this morning. It is, in fact, David Livingstone, reflecting on his experiences in Africa in the 1850s.

What makes globalisation today appear so dramatic and sometimes controversial, Mr Chanda reckons, is its visibility. He points out that in 1453 it took 40 days for the pope to learn that Constantinople had fallen to the Turks. In 2001, by contrast, “the twin towers of the World Trade Centre fell in real time, on live television, as the world watched on in horror.”

Such examples hint at the fragility of a globalised world. The closer the connections between the parts, the more vulnerable the whole system becomes to any major wobbles. The fall of the Roman Empire, the Black Death, the collapse of trade and migration in the interwar years of the 20th century: all these either slowed the process of globalisation or stopped it in its tracks, albeit only temporarily. The threats we face today—from a superbug like SARS, for instance, or from Islamist terrorism—can go global faster than any of the threats in the past. On the positive side, so can our response to them.

Mr Chanda makes a solid and attractive case for globalisation and its potential as a force for good. But he also has a great deal of sympathy for globalisation's losers. In his closing chapter he notes coolly that “more than a billion people live on less than a dollar a day, and most are likely never to have made a phone call or to have travelled beyond their place of birth.” In view of all that has gone before, this one simple point has more impact than any number of tractor-borne assaults on American fast-food restaurants by over-subsidised continental gourmets.